Lifting jack



H. W. CLARK Dec. 30,1930.

LIFTING JACK F-iled .Aug. 19, 1927 Patented Dec. 30, 1930 UNITED STATESPATENTOJFFECE HAROLD W. CLARK, F ALLIANCE, OHIO, ASSIGNOR TO, THEBUCKEYE JACK MANUFAC- TURING COMPANY, OF ALLIANCE, OHIO LIIETING JACKApplication filed August 19, 1927. Serial No. 2141154.

This invention relates to improvements in lifting jacks, with specialreference to an improvement in the form of structure of the jack frameand frame base.

In order to obtain the maximum strength with the least possible weightof material, it has been the custom to make the base or lower part ofthe frame of the jack either of a single web section or of open boxsection. The disadvantage of the single web section for base is thatwhen loads are applied eccentrically, the base has a tendency to bend atthe edges and take a permanently curved form, so that thereafter thebase of the jack will not rest securely upon any level surface but willhave a tendency to tilt or tip when a vertical load is appliedespecially where the load is applied to the foot of the lifting rack.lVhere the base is made of the open boX section, while the edges aresupported by the diagonal walls yet the curve where this wall joins thehori- Zontal bottom plate presents a weak point and the bottom of thejack will have a tendency to bend upwards and dish. a This distorts thebottom member and renders the jack ineflicient when set on a flat bed.

In order to overcome the bending of the edges which occurs when thesingle web section is used, and in order to strengthen the bottom plateagainst the dishing action, I make the edges of the lower plate ofsingle web section and then core the inside of the base out so as tomake flaring upward extending walls to meet the lower member of thecasting, and it's-enforcing the opening at the top of the section withtwo vertical walls to further assist in preventing any bending of thebase. I further insert vertical walls or webs in the front or toe of thebase and also at the rear to strengthen the same and to prevent anybending or curving of the same under load either at the toe or at therear of base.

The object of the present invention is to provide an improved base forjack frame, providing an economical distribution of the metal therein soas to provide great strength against distortion, at the same timekeeping the weight of the metal as small as possible.

F ig. 1 is a side elevation of a j ask frame and base, showing theprojecting foot of the lifting rack.

Fig. 2 is a horizontal section on line a@ of Fig. 1 with rack omitted.

Fig. 3 is a front elevation showing section of base taken on line 6-4)of Fig. 1, with rack omitted.

Referring to the drawing, 4 represents the hollow central standard ofthe jack frame in which the lifting rack 5 with its outwardly projectingfoot 6 is slidably mounted being guided by vertical guides 7 cast aspart of the frame. The rear wall of the frame is strengthened by rib 8which is provided with opening 9 to serve as a hand grip for the jack.The outer flange of rib 8 is strengthened by flat oval shaped section10, which can be easily gripped as a handle.

The base instead of being either cored out to form a hollow section orbeing of single web or solid section, is made of the form shown which isbest shown in plan in Figure 2. The central part is cored out hollow,and

the flaring side walls 10 and the front and back walls 11 and 12respectively join with the bottom member 13 along a line 14 which isconsiderably within the outer edge 15 of the base. The back and sidewalls are curved inwardly and upwardly from the bottom to meet thevertical members of the frame 4:. The front wall 11 extends diagonallyupward from the bottom and is supported by internal rib or web 16 tostrengthen the toe of the base against bending. Vertical strengtheningrib or web 17 is provided in the rear of the base to strengthen thatpart against bending and to stiffen the bottom plate 13 from dishing.

The bottom member 13 of the base is of uniform thickness and is cut outat 18 in approximately rectangular form to permit of the insertion. orwithdrawal of the lifting rack 5 with its projecting foot 6. Thisopening may vary in shape or in size depending upon the shape and sizeof the lifting rack. In order to supply the necessary strength toprevent breaking or bending of the toe or front 19 of the base, Iincrease the section of the metal at 20 and reinforce the opening 21with two heavy horizontal members gradua-lly increasing in thicknessfrom the part of the toe 22 to where the front wall meets the mainvertical frame at 23.

With the base as I have shown it, there is a heavy single web flangeextending complete- 1y around the base, supported against bendng by thefront rear and side walls, my ob ject being: to provide a base properlydesigned to prevent bending at the edges and at the same time to keepthe weight of metal as small as possible and to prevent the bottom platefrom dishing or becoming concave under loads.

I have provided on the vertical body of the frame reinforcing ribs 24 onboth sides of the frame, cast integrally with the frame and extendingfrom the inside of the wall, inwardly. These ribs are just high enoughto clear the rack which operates up and down in the center of the frame.The purpose of these reinforcing ribs is to strengthen the frame castingagainst breaking transversely at the central part of the body where sidestrains are usually encountered.

I have shown my base in connection with what is known in the trade as atrip ack but it will be obvious that the same type of base can be usedwith any of the other kinds of jacks commonly used for railroadconstruction, automobile, & etc.

What I claim is A frame for a lifting jack comprising an oblong base ofcored out section, a single web bottom plate with an opening formedtherein, an oblique front wall, a toe formed by the junction of theoblique front wall and the bottom plate, and a rib formed within the toeand integral with the bottom plate, the said rib being locatedapproximately in the center of the toe and in the plane of the openingin the bottom plate.

In testimony whereof, I have signed this specification.

HAROLD IV. CLARK.

